Have you ever published anything?

Yes, some scientific, peer-reviewed papers which I co-authored.
Long time passing... 😏

I write and then bin much like Mark Twain. I write for my own pleasure unfortunately writing now is a massive money earner for third party interests. Agent, editor, publisher, few thousand dollars or quid "might" get you published. I take in everything in that Stephen King said in his book about "On Writing" and he said that those mentioned are a necessary evil. How true. Must be millions of good stories laying in wastepaper bins because the writer can't afford the extortionate payments to get published. Go the competition route and it is the same, magazines need the palms crossed with silver too. Ho-hum.

Yes, I did publish a few books.

As a journalist; magazine articles as well as straight news stories. But not a book. One of the reasons I retired early was to write a book or two. Found I did not have the discipline to plow on and edit at the end; constantly editing and re-writing, churning as I went. I did write a three-volume journal of observations on life for my grandkids that I gave them when they reached adolescence. Of course the publishing industry is so much different than when I retired. So much is now an Internet-driven form of self-publishing. Three former members of my former staff have recently published books, which makes me wonder "what if. . ." particularly when one -- who now has published two books -- gave me a copy of his first with the comment "you are the fastest, good writer I've ever known. I've known other fast writers, and other good writers, but not the combinations". Which gets back to the writing on deadline and not having the luxury to self-edit.

I’ve had my work published on the front cover of magazines.

One of my photos was used in a book.

A few scientific papers and patents

I plan to. Getting there.

Yes - a chapter in an early book about eCommerce and an academic thesis on a very obscure domain relating to speech perception and automatic speech recognition systems.

And several hundred thousand tweets.

A couple of short stories, a dozen or so poems, some book reviews, several hundred illustrations.

Yes, actually

I had a weekly byline in a local paper for a youth sports team once!

Print and online magazine articles etc

Potato scientific papers, yes.

Probably

Yes

Ish. Yes

No, but I am writing a book that I would like to have published when I am done.